During their three-day meeting this week, Japanese Prime Minister Shinzo Abe again asked U.S. President Barack Obama to speed up exports of American natural gas to help his beleaguered and energy-poor economy. But the big energy revolution that could ride to Tokyo's rescue may not come on tankers from U.S. ports, but rather from deep underneath the sandy seabed off Japan's own shores.

Methane hydrates, which are chunky packets of ice that trap huge amounts of natural gas in the form of methane, are looming ever larger in Japan's plans to meet its needs for energy in the wake of the Fukushima nuclear disaster and skyrocketing bills for imported fuel.